Then he wished he hadn’t said that. He remembered thinking he’d hear the alarm clock waking him up, that very first time, and then he recalled the shock of realizing that he wasn’t being allowed to wake up at all.

‘You know, I don’t want to find out,’ he added.

‘Without engines, we cannot turn the ship around,’ said the Captain. ‘I am sorry. You were too keen to save us.’

‘It is getting bigger,’ said Kirsty. ‘You can tell, if you watch the stars behind it.’

‘I am sorry,’ said the Captain again.

‘At least the ScreeWee should make it,’ said Johnny.

‘I am sorry.’

Kirsty stood up. ‘Well, I’m not,’ she said. ‘Come on!’

She picked up the gun and strode away into the shadows. Johnny ran after her.

‘Where do you think you’re going?’

‘To the escape capsule,’ she said.

‘What escape capsule?’

‘Indeed,’ said the Captain, scuttling after them, ‘I ask that too. There is no such thing.’

‘There can be if we want there to be,’ said Kirsty, opening the door. ‘You said the game is made up of things we know? Well, I know it’ll be right down under the ship.’

‘But—’

‘It’s my dream as well as yours, right? Believe me. There’ll be an escape capsule.’ Her eyes had that gleam again. She hefted the gun. ‘I know it,’ she said. ‘I’ve been there.’

He remembered her room. He could picture her sitting there, with a dozen sharp pencils and no friends, getting top marks in her History homework, while in her head she was chasing aliens.

‘I cannot understand,’ said the Captain.

The corridor outside was full of steam. The ship might cross the Border, but it was going to have to have a lot of repairs before it ever came back.

‘Um,’ said Johnny. ‘It’s a bit like the models in the cereal packets. It’s . . . kind of a human idea.’

The ScreeWee hesitated in the doorway. Then she turned to look at the screen.

‘We are getting closer,’ she said. ‘If you think there is something there, then you must go now.’

‘Come on!’ said Kirsty.

‘Uh—’ Johnny began.

‘Thank you,’ said the Captain, gravely.

‘I haven’t really done much,’ said Johnny.

‘Who knows? You never thought of yourself. You tried to work things out. You made choices. And I chose well.’

‘And now we must go!’ said Kirsty.

‘Perhaps we shall meet again. Afterwards. If all goes well,’ said the Captain. She took one of Johnny’s hands in two of her own.

‘Goodbye,’ she said.

Kirsty caught Johnny’s shoulder and dragged him away.

‘Nice to have met you,’ she said to the alien. ‘Sort of – interesting. Come on, you.’

Some of the lights had gone out. The corridors were full of steam and vague shapes. Kirsty ran on ahead, darting from shadow to shadow.

‘We’ll have to go down,’ she said over her shoulder. ‘It’ll be there. Don’t worry!’

‘You’re really into this, aren’t you,’ said Johnny.